The art is replete with staplers that close a staple into a closed loop (which loop may be generally rectangular or D-shaped) by bending one or more parts of a central portion of the staple against an anvil so that the staple is closed around the anvil and projecting end portions of the open staple can enter and join living tissues adjacent the anvil (such as portions of disunited skin), and the closed staple which will then hold the tissues together. Illustrative examples of patents describing such staplers include U.S. Pat. Nos. 3,873,016; 4,109,844; 4,202,480; and 4,321,002.
Typically, the anvil in such a stapler is cantilevered, projects past a guide surface for the staple, and has one or more surfaces against which a staple is bent closed, which surfaces may include opposite edge surfaces spaced at a distance corresponding to the distance between spaced parts of the staple to be bent, and/or a contact surface adapted to engage a central portion of the staple to be bent. Means are provided for positioning an open staple at the anvil with the central portion of the staple adjacent the anvil and the end portions of the staple flanking the edge surfaces of the anvil. A ram is mounted on the housing for movement from a load position affording positioning a staple along the guide surface adjacent the anvil, to a formed position so that the ram will bend the staple closed around the anvil and the end portions of the staple can enter adjacent tissues. After the staple is thus closed, the anvil must be pulled from within the closed staple by manually moving the housing of the stapler which is annoying to the user. Also, if this is not first properly done, an attempt to move the housing of the stapler away from the tissue engaged by the staple will pull on the staple and can cause damage to the engaged tissue.